Gas turbine engines must be run at very high temperatures, particularly in a combustor section thereof where engine fuel is burned in combustion with high pressure air to form high temperature, high pressure combustion gases. These gases are used downstream of the combustor by a turbine section where the kinetic energy of the gases powers the engine. Therefore, it is desirable to increase the temperature of the combustion gases for more effective engine performance. However, the durability of an engine fuel system, particularly of fuel nozzles, is challenged in such an elevated temperature environment. The fuel nozzles are typically mounted to a hot engine case from which heat is transferred to the fuel nozzles. Therefore, fuel leakages and internal nozzle blockages caused by the heat transferred to the nozzles are always issues of concern for engine designers.
Accordingly, there is a need to provide an improved fuel nozzle structure and/or fuel nozzle installation structure in gas turbine engines, in order to prevent fuel leakages and internal nozzle blockage caused by the heat from such an elevated temperature environment.